1. Field of the Invention
The present invention relates to a laundry drier, and more particularly, to a laundry drier control method in which a temperature variation rate per unit time is used to control drying time as needed.
2. Discussion of the Related Art
A laundry drier is an apparatus for drying wet objects, e.g., clothes, after completion of a washing cycle or the like. FIGS. 1 and 2 illustrate a laundry drier according to a related art, with FIG. 2 showing a cross-section taken along a line I-I in FIG. 1.
Referring to FIGS. 1 and 2, a drier according to a related art is comprised of a body 100 having an entrance 101 at a front side in which a door 105 is installed, a drum 30 rotatably installed in the body and having a plurality of stirrers 30a protruding from an inner circumferential surface of the drum, a motor 50 fixed to an inner side surface of the body to generate and transfer via a belt 60 a slow and directionally controllable rotational force with respect to the drum, first and second hot air passages 10a and 10b for guiding an air flow of external air (10a) to drum's interior to be discharged (10b) to the exterior of the laundry drier, a heater 20 installed inside the first hot air passage to heat the air therein, and an exhaust fan 40 for generating a forcible blowing force to discharge air through the second hot air passage and thereby draw in external air through the first hot air passage.
Referring to FIG. 3, illustrating a laundry drying method according to the related art, with wet laundry placed in the drum 30, drying is initiated in a step S10 to actuate each of the exhaust fan 40, the heater 20, and the motor 50. As the exhaust fan 40 starts to operate, external air is drawn in through the first hot air passage 10a, where it is heated by passing through the heater 20 and forcibly led into the drum 30, to evaporate the water content of laundry placed therein. Thus, the drying action is realized by a negative blowing force of the exhaust fan 40, whereby a circulation of air is achieved by drawing in external air through the first hot air passage 10a and discharging the air through the second hot air guide passage 10b. Meanwhile, the drum 30 is rotated according to a predetermined cycle, and the stirrers 30a pull the laundry up one side of the drum's interior to fall back down into a lower area thereof. The laundry is dried in a step S20 through the above-explained process.
As drying thus proceeds, if it is determined in a step S30 that a predetermined time has passed, the heater 20 and motor 50 are stopped in a step S40. Here, the exhaust fan 40 continues to operate for a fixed predetermined time of say, five minutes, to perform a cooling of the interior of the laundry drier in a step S50, after which the door 105 may be opened. Thus, the cooling is performed according to a procedure similar to that of the steps S20˜S40 in which a constant operation is continued for a fixed duration.
As above, the laundry drier of the related art completes its assigned task by execution according to a predetermined time. That is, the drying procedure is performed for a fixed time, as set by the manufacturer, regardless of the amount or type of laundry being dried. Therefore, drying may be incomplete or excessive.